On Fri, 22 May 2009, Andrew Daviel wrote:
If in Thunderbird the option "server supports folders which can contain
both folders and messages" is checked
No client should ever have, or need, such a configuration option. This is
handled by the IMAP protocol.
With the option set, the GUI has a single option "create subfolder".
With it clear, it asks if you want a folder or a directory.
The missing piece of your puzzle is that it is perfectly reasonable to
have a "directory-only" object in a "dual-use" work where a name can be
both a mailbox and a directory.
Consider USENET newsgroups. The fact that comp.mail.pine and
comp.mail.imap both exist does not mean that there is a mailbox called
comp or comp.mail. Yet both comp and comp.mail are superior directories
of comp.mail.imap and comp.mail.pine.
The same thing happens in IMAP mailboxes. You can create directories to
hold mailboxes without making them also be mailboxes. The only thing that
changes with dual-use mailbox names is to allow a mailbox to also act as a
directory.
This also happens if you delete a mailbox that has children. This causes
the mailbox to become a directory, since the children are not deleted.
That is, if you have the following mailboxes:
junk
junk/crap
junk/cruft
and you then delete "junk", then you still have a directory named "junk"
containing mailboxes "junk/crap" and "junk/cruft".
As far as I can see, with MBX or Unix, "create test" will
do open ("test", O_RDWR) and "create test/" will do mkdir ("test").
Yes. mbx and unix as single-use mailbox formats.
In RFC 3501 you say "If the mailbox name is suffixed with the .. hierarchy
separator .. the client intends to create mailbox names under this name".
Which implies that the client needs to know which to create.
Correct. Which is why the "server supports folders which can contain both
folders and messages" option is stupid.
Since the server
workings are (rightly) hidden from users, and the paradigm is that a folder
on a GUI desktop contains both files and folders, users will assume that a
folder can contain both subfolders and messages.
Why? Is it because of the stupid name "folder" and what it meant on the
Macintosh?
I have yet to hear anyone saying that files should contain other files.
Yet that is what these poorly-designed GUIs are doing.
Maybe I am missing something, but I can't see anything in the protocol for a
client to determine whether a server can create subfolders without testing
it.
That's because that's the wrong thing to test. It has NOTHING to do with
what a server can do, and EVERYTHING to do with the underlying mail store.
The client needs to declare what type of object to create. Either it
creates a directory, or it creates a mailbox. In the case of creating a
mailbox, it can then determine -- AFTER the mailbox is created -- whether
it is also a directory.
That client decision point is ALWAYS there.
-- Mark --
http://panda.com/mrc
Democracy is two wolves and a sheep deciding what to eat for lunch.
Liberty is a well-armed sheep contesting the vote.
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